ADT7320UCPZ AD [Analog Devices], ADT7320UCPZ Datasheet - Page 18

• Manufacturer Part Number: ADT7320UCPZ
• Manufacturer: AD [Analog Devices]

ADT7320
SERIAL INTERFACE
The ADT7320 has a 4-wire serial peripheral interface (SPI). The
interface has a data input pin (DIN) for inputting data to the device,
a data output pin (DOUT) for reading data back from the device,
and a data clock pin (SCLK) for clocking data into and out of
the device. A chip select pin ( CS ) enables or disables the serial
interface. CS is required for correct operation of the interface.
Data is clocked out of the ADT7320 on the negative edge of SCLK,
and data is clocked into the device on the positive edge of SCLK.
SPI COMMAND BYTE
All data transactions on the bus begin with the master taking
CS from high to low and sending out the command byte. This
indicates to the ADT7320 whether the transaction is a read or a
write and provides the address of the register for the data transfer.
Table 15 shows the command byte.
Table 15. Command Byte
C7
0
C6
R/W
C5
Register address
C4
C3
C2
Continuous read
MICROCONTROLLER
Figure 15. Typical SPI Interface Connection
C1
0
Rev. PrA | Page 18 of 24
C0
0
SCLK
DOUT
DIN
CS
ADT7320
GND
V
INT
Bit C7 of the command byte must be set to 0 to successfully begin a
bus transaction. The SPI interface does not work correctly if a 1
is written into this bit.
Bit C6 is the read/write bit; 1 indicates a read, and 0 indicates a write.
Bits[C5:C3] contain the target register address. One register can
be read from or written to per bus transaction.
Bit C2 activates a continuous read mode on the temperature value
register only. When this bit is set, the serial interface is configured
so that the temperature value register can be continuously read.
When the command word is 01010100 (0x54), the contents of
the temperature value register can be read out without requiring
repeated writes to set the address bits. Simply sending 16 SCLK
clocks to the ADT7320 clocks the contents of the temperature
value register onto the DOUT pin.
CT
DD
V
DD
0.1µF
PULL-UP
10kΩ
V
DD
10kΩ
Preliminary Technical Data